1, /metadata/aconfig is the directory that stores aconfig storage
related protobuf files and flag value files boot copy. Grant read
access to everybody. But limit the write access only to init and
aconfig storage service process (to be created later)
2, /metadata/aconfig/flags is the sub directory that stores persistent
aconfig value files.Initially set it up to be accessible by
system_server process only . When aconfig storage service process is
created, will add another permission to storage service process.
Context to why we are hosting flag data on /metadata partition:
Android is adopting trunk stable workflow, flagging and A/B testing is
essential to every platform component. We need some place to host the
flag that are accessible to system processes that starts before /data
partition becomes available.
In addition, there has been a long discussion regarding utilizing
/metadata partition for some process data, another example is mainline
modules, we are trying to make them to be able to be mounted earlier,
but cannot due to /data availability.
Bug: 312444587
Test: m
Change-Id: I7e7dae5cf8c4268d71229c770af31b5e9f071428
6c8210da20